1. Field of the invention
The present invention relates to a unit for packaging and dispensing a liquid or semi-liquid, or even highly viscous, product. It is especially suited to the packaging and spraying of liquid products (such as scents) used in the field of cosmetics or of dermo-pharmacology. The invention is specifically suited to devices with a manually operated pump.
2. Background of the Related Art
Devices for spraying liquid, either by means of a manually operated pump, or by means of a valve used in conjunction with a pressurized liquid, are well known. Typically, the valve or the pump is actuated by a push-button mounted on a hollow stem, which is mounted on elastic return means and is capable, under the effect of a pressure exerted on the push-button, of being depressed so as to place the passage defined inside the hollow stem in communication with the contents of the reservoir. This communication allows liquid to be dispensed through an outlet member connected to the said passage. When the pressure ceases, the hollow stem rises back up by elastic return, thus interrupting the dispensing of the product. The outlet member may consist of a nozzle or any other spray member such as a mesh, or a porous member, etc.
The effectiveness of the system, particularly the minimum force necessary for actuating the dispensing element (that is to say the efficiency), depends to a great extent on the way in which the actuating pressure is transmitted to the pump stem. This problem arises in particular when the force exerted on the push-button is not directed exactly along the axis of the stem but is offset, which causes a stress at the pump stem which has both a vertical component and a horizontal component. When there is a rigid coupling between the stem and the push-button, a slight jamming of the stem occurs. This impedes its correct retraction into the pump body and means that a greater bearing force has to be exerted in order to produce the stem depression needed to actuate the pump.
FR-A-2 692 235 describes a device for dispensing a liquid product comprising a container equipped at the top with a dispensing member bearing a push-button, and a cap fitted with an actuating member in the form of a lever articulated to the cap and equipped with a bearing means acting on the upper outer surface of the push-button, the articulation between the actuating member and the cap being situated, heightwise, halfway along the travel of the push-button. The upper outer surface of the push-button is a convex spherical surface, and the bearing means is a circular ring, the annular lower end of which defines a spherical bearing surface that complements that of the upper outer surface of the push-button.
Although the device described in this document is satisfactory in certain respects, it poses a certain number of problems. This is because the coupling between the push-button and valve stem is a fixed coupling as in conventional devices. Only the coupling between the bearing surface and the push-button is achieved by means of a connection in the form of a spherical surface against which a surface of complementary shape bears. This does not fully solve the problem of the jamming of the valve stem, which still partially remains, depending on the position at which the bearing force is applied to the bearing surface. Furthermore, because of its design, the system is complicated and expensive to produce. What is more, pump or valve actuation do not occur effectively unless the bearing force is exerted on a localized region of the bearing means, namely essentially opposite the articulation between the actuating member and the cap. Finally, because of the complexity of its design, the system is relatively fragile.
What is more, in the device described in the patent discussed above, the product-outlet nozzle is integral with the push-button. Thus, when the pump or valve is actuated, the push-button is depressed axially, as is the product-outlet nozzle. A problem then arises which is similar to the one which will now be described in greater detail with reference to a certain number of other documents of the prior art.
By way of example, utility certificate application FR 2,682,937 describes a spray device of the type with a pump, comprising a pump mounted on a bottle, and comprising a hollow stem which acts as an outlet duct and as an actuating member, and can move within the pump body against the action of a spring. A dispensing cap is mounted on the bottle on top of the pump, and comprises a pressure-actuated element equipped with means of mechanical coupling to the hollow stem. The cap also comprises a spray nozzle and an internal passage which opens into the nozzle, as well as connection means serving to place the hollow stem in communication with the internal passage in the cap. According to this document, the connection means comprise a flexible tubular element coupled at one end of the hollow stem and at the other end to the internal passage of the dispensing cap. To dispense some product, the pressure-actuated element is depressed, which causes actuation of the pump, and liquid to emerge through the outlet nozzle via the hollow stem, the flexible tubular element and the internal passage. Under the effect of the actuating pressure, the upper part of the cap carrying the nozzle flexes at a connecting region located beneath the nozzle.
The major drawback of a device of this kind stems essentially from the fact that actuating the pump causes a substantial change in the position of the nozzle (by pivoting), which change causes a change in orientation of the sprayed liquid. Inevitably, if no precautions are taken, the product will not be sprayed in the desired place. Another device of the same type, and therefore with the same drawbacks, is described in EP-A-0,747,131.
In EP-A-0,385,077, just as in FR-A-2,692,235, actuating the pump causes an axial movement of the outlet nozzle which, in the same way as for the device discussed earlier, has to be taken into account when positioning the spray device with respect to the surface to be treated, so that the product will be sprayed exactly in the desired place. Furthermore, such a design makes it necessary to produce an oblong orifice opposite the nozzle, the axial height of which orifice depends on the amplitude of the axial movement of the nozzle. Such an orifice of elongate shape has a not insignificant affect on the aesthetic appearance of the device.
U.S. Pat. No. 3,149,761 and EP-A-556,128 both describe a push-button mounted on a valve stem via a ball-joint connection. In both these documents, product is discharged essentially along the axis of the valve stem. If there is a desire to make the outlet orifice lateral, in particular, with respect to the axis of the container, then the same problem as described with reference to the devices discussed earlier, namely that of the movement of the outlet nozzle when the dispensing member is actuated, arises. The problem is all the more noticeable where manually operated pumps with an actuating travel of several mm are involved. In the case of a valve, the actuating travel at the time of opening is only a few hundredths of a millimeter.